Diisocyanate, polyurethane preparation

In a recent patent, Reuter (110) describes a polyurethane prepared from PTHF (mol. wt. 1000 to 3000), 1,4-butanediol, and OCN(CH2)6CN0. In another case Murbach and Adicoff (67) interrupted the regularity of PTHF by copolymerization with ethylene oxide before chain extension with diphenyl-methane-4,4 -disiocyanate. Dickinson (99) prepared a series of polyurethane elastomers from THF-PO copolymer diols and 2,4-tolylene diisocyanate. He found that the use of copolymers with approximately 75 wt.-% THF led to polyurethanes with very good properties relative to the use of propylene oxide homopolymer. 

A number of bark-diisocyanate polyurethane foams were prepared. An area which I felt had to be explored was whether I was producing a polyurethane foam from the reaction of bark and diisocyanate. Initial attempt to elucidate or confirm a urethane linkage in the prepared foams, was made by the Infra-red analysis on a series of three prepared polyurethane foam formulas, wherein the bark was the varying factor. The three prepared foam formulations studied are shown in Table IV. Infra-red analysis was conducted on the three foam formulations listed in Table IV. The resulting curves are shown in Figure 2. 

Then, polyurethanes based on aromatic diisocyanates were prepared. The same fluorinated diol was involved in the synthesis of such polymers with 3,5-tolylene diisocyanate and with a mixture of 2,4-tolylene diisocyanate and 3,3 -bitolylene-4,4 -diisocyanate [77]. 

In the polyurethane industry, the polymeric glycols are prepared by anionic polymerization of epoxides such as ethylene oxide and propylene oxide. Poly(tetra-methylene glycol), which was prepared by polymerization of tetrahydrofuran, was subjected to chain extension by reaction with diisocyanate (polyurethane formation) and with dimethyl terephthalate (polyester by alcoholysis). 

The value of a for poly(propylene oxide) was obtained from the data of Moacanin 189) for polyurethanes prepared by condensation of toluene-2,4-diisocyanate with atactic polypropylene glycols of molecular weights about 1000 and 2000. The small quantity of diisocyanate present in these compositions can make only a negligible effect on the chain dimensions (less than one per cent on the freely rotating chain, as is... 

Polyurethanes containing polytetrahydrofuran, diethylene glycol, stearyl alcohol, and hexamethylene diisocyanate were prepared by Meffert [1] and used in hair compositions. 

It can be seen from Table XIII data that control Polymer 7 is a high molecular weight and high quality polyurethane whereas the modified polymerization yielded lower molecular weight Polymer 19 with good but lesser properties. The lowest final (16 minute) [NCO] was obtained in the polyurethane prepared with a diisocyanate deficiency in the charging recipe. 

Starch polyurethane foams could be converted into sorbents for water when starch-acrylonitrile or starch-methacrylonitrile graft copolymers were crosslinked with diisocyanates.2655 2656 Such polyurethanes have been proposed as occlusive wound dressings,2657 as well as sizes for cotton yams.2658 Starch polyurethanes for reinforced paper were produced in reaction of iV-chlorocarbamoylethyl starch with cresol or thiolignin.2659 The addition of mineral salts to polyurethanes prepared from starch and urea improved their performance as adhesives.570... 

Vegetable oil-based polyols obtained by epoxidation are treated with diisocyanates in the presence of a suitable chain extender and catalyst to obtain polyurethanes (Fig. 6.5). Polyurethanes have been prepared from olive, peanut, canola, corn, soybean, safflower and sunflower oil by the conventional epoxidation process, followed by treatment of the polyols of the epoxies with diphenylmethane diisocyanate. Polyurethane resins may also be obtained by the treatment of soybean polyols (which are obtained by methanolysis of epoxidised soybean oil with isocyanates at a temperature of 50°C) or from epoxidised linseed oil with TDI using xylene as the solvent. 

The most frequently encountered acid is adipic, but others are also employed in polyurethanes. Polyurethanes prepared from poly(ethylene glycol) adipate and 1,5-naphthalene diisocyanate produce two strong absorptions at 750 cm and 735 cmwhile the urethane from poly(ethylene glycol) sebacate and 1,5-naphthalene diisocyanate shows crystallinity bands at 722, 729, 754, 860, 881 and 895cm" ... 

Lipatov and co-workers synthesized sequential IPNs containing a reinforcing silica filler as follows Polyurethane samples based on oligo-ethylene glycol adipate and tolylene diisocyanate were prepared with various levels of Aerosil, a silica filler. Trimethylolpropane was used as the... 

Wang Y, et al. Degradation studies on segmented polyurethanes prepared with poly (d, L-lactic acid) diol, hexamethylene diisocyanate and different chain extenders. Polym Degrad Stab 2011 96(9) 1687-94. 

A hydroxy-terminated polyurethane, prepared from ethylene glycol (EG) (0.5 mol) and 2,4-toluene diisocyanate (TDI) (0.3 mol), exhibits an N—H band at 1470 and 2050 nm. The 2050 nm band undergoes a large increase upon heat curing [16]. 

Figure 9. Williams plasticity of polyurethanes prepared from poly-(propylene ether) diols at d erent ratios of 2,4-tolylene diisocyanate...

Condensation polymers containing sucrose or glucose units in the main chain were also reported. Cross-linked polyurethanes prepared from polyethylene glycol (PEG), diphenylmethane diisocyanate (MDl) and a sugar (glucose, fructose, or sucrose), were reported by Zetterlund et The storage modulus, the Tg, and the stress at break increased with an increase of sucrose content and the strain at break decreased with an increase of sucrose content. 

Methanediphenyl diisocyanate (MDI) is used to prepare a polyurethane. Draw the structure of a polyurethane prepared from MDI and ethylene glycol. 

The formation of the TPE follows the classical polyurethane preparation (Scheme 45) end-capping of I by methylene-bis(4-phenylisocyanate) followed by the polyaddition of the mixture of II, 1,4-butanediol, and the diisocyanate. 

For BTA/DMG polycondensation t = 3.11 is found using a Weissenberg rheogoniometer (lowest frequency 0.1 s ), and for the polycondensation of polyurethanes prepared from hexamethylene diisocyanate and a polyoxypropylenetriol (with and without solvent and using a magnetic sphere rheometer with a frequency near 2 X 10 s ) the exponent t = 3.3 0.3 was obtained Therefore, it seems that the exponent t for the shear modulus of polycondensation samples is very close to the classical exponent value of 3. 

The hydroxyl groups can be esterified normally the interesting diacrylate monomer (80) and the biologicaky active haloacetates (81) have been prepared in this manner. Reactions with dibasic acids have given polymers capable of being cross-linked (82) or suitable for use as soft segments in polyurethanes (83). Polycarbamic esters are obtained by treatment with a diisocyanate (84) or via the bischloroformate (85). 

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